1. Field of the Invention
This invention relates generally to the provision of an apparatus for feeding or advancing predetermined increments of spine fin heat exchanger tubing during the manufacture of a serpentine heat exchanger. More particularly, the invention relates to an advancing system wherein a body member having a passageway for coaxially receiving the heat exchanger is reciprocated between an advancing stroke and a resetting stroke. The passageway is dimensioned to provide engagement between the distal ends of the fin members and the passageway wall, that is sufficient to cause the heat exchanger tubing to be fed axially the predetermined increment during the advancing stroke while allowing the body member to travel through the resetting stroke during which time the heat exchanger is held against axial movement.
2. Description of the Prior Art
In the manufacture of serpentine heat exchangers the machines include a feed mechanism that advances tubing in preselected increments to a bending head which successively bends each increment in alternate directions. In some instances a mandrel occupies the inside of the tube to maintain its roundness during the bending operation. In this instance the mandrel may be used to advance the heat exchanger tubing by moving the mandrel the preselected increment or distance. In some instances the serpentine heat exchanger is formed without employing an internal mandrel, and means must be provided for advancing the tube by externally engaging the tube. When the heat exchangers are formed of spine fin tubing such as produced by the machine shown and described in U.S. Pat. No. 3,688,375-Venables, assigned to the General Electric Company, assignee of the present invention, great care must be exercised to prevent the spine fins from being deformed which could result in loss of heat exchange efficiency. A typical machine for forming serpentine spine fin heat exchangers that does not employ an internal mandrel is disclosed in Ser. No. 677,505-Durbin et al., now U.S. Pat. No. 4,048,834 also assigned to the General Electric Company.